Functional specialization of the glycosylphosphatidylinositol membrane anchor

Abstract

The discovery of GPI-anchored membrane proteins presented a conundrum for membrane biologists. What could the special purpose be for this type of membrane anchor and why couldn't a transmembrane anchor do the same job? Recent information from several different sources is beginning to provide answers to these questions. In this review, evidence is presented that GPI-anchored membrane proteins are uniquely adapted for delivering to the cell both nutrient and signaling molecules or ions using two distinct endocytic pathways. So far, they are the only surface molecules known to have this capability.